This invention relates to a process of handling rolls of roofing material and stacking the rolls of roofing material onto a shipping pallet.
Rolled roofing material is generally made of a glass fiber reinforced asphalt matrix with protective granules coated on one of the surfaces. The rolled roofing material is manufactured in long sheets which are then rolled for ease of handling and transporting. The sheets of rolled roofing material are typically manufactured in 3-foot wide sheets and then rolled by a roll-up machine to a diameter of about 9 inches. The rolls of roofing material exit the roll-up machine on a conveyor and are typically oriented in a horizontal position. A plurality of rolls of roofing material are then xe2x80x9cpalletizedxe2x80x9d or loaded onto a shipping pallet for storage and transportation. The rolls of roofing material are placed vertically on the pallet such that they stand on end. The plurality of rolls of roofing material on the pallet are then often banded together for stability on the pallet.
In the past, the rolls of roofing material were palletized by workers manually lifting each roll from the conveyor and placing them on the pallet. However, the rolls of roofing material are relatively heavy and can weigh around 36.3 kg (80 lbs.) each. Therefore, the rolls of roofing material are cumbersome to manually handle. Manually lifting each roll is also labor intensive and time consuming.
For these reasons, automated upender machines or xe2x80x9cupendersxe2x80x9d have been used to palletize the rolls of roofing material. Automated upenders typically include a platform or table for receiving a plurality of horizontally oriented rolls of roofing material from the conveyor. For a conventionally sized pallet, four or five rolls of roofing material in a linear arrangement can be loaded at a time onto the table. The rolls of roofing material are loaded onto the table by automated actuator arms which push the rolls of roofing material from the conveyor onto the table. After the rolls of roofing material are loaded on the table, the table is pivoted to a first vertical position by a pneumatic or hydraulic cylinder. The rolls of roofing material are supported by a bottom ledge extending from the table. A pair of movable side plates positioned adjacent the outermost rolls of roofing material are moved by actuators so as sandwich the plurality of rolls of roofing material. The side plates help prevent the rolls of roofing material from moving or shifting when pivoted from the horizontal position to the first vertical position. Additional actuators then translationally move the table in a horizontal direction to a second vertical position above a pallet. The ledge is then retracted by actuators, thereby dropping the rolls of roofing material onto the pallet.
The table is then moved back to the conveyor to load another batch of rolls of roofing material. The table is moved from the first vertical position to the second position by the same distance every time. Therefore, the pallet must be moved or indexed so that the next load of rolls of roofing material is properly positioned on the pallet adjacent the previously load of rolls of roofing material. To accomplish this task, the pallet is connected to an automated indexing machine which automatically re-positions the pallet after every load of rolls of roofing material. Although the automated upender and the pallet-indexing machine perform satisfactorily, the automated machines are very costly to manufacture and maintain. The automated upender and indexing machine can also occupy a large quantity of floor space.
It is an object of the present invention to provide a method of palletizing rolls of roofing material that eliminates the need for manual product orientation.
It is another object of the present invention to provide a method of palletizing rolls of roofing material which includes two alternative rotation configurations for orienting rows of rolls of roofing material.
It is an object of the present invention to provide a method of palletizing rolls of roofing material which is relatively inexpensive and highly reliable.
The above objects as well as other objects not specifically enumerated are achieved by a process of loading rolls of roofing material onto a stationary pallet, wherein the process performs a series of operations, in accordance with the present invention. Each operation includes the steps of: (a) loading rolls of roofing material onto an upwardly inclined conveyor; (b) depositing the rolls of roofing material onto a downwardly inclined table; (c) dropping the rolls of roofing material onto a sloped, rotating table until the desired number of rolls of roofing material are accumulated; (d) rotating the table and then tilting the plate until it is nearly upright into a vertical position; (e) traversing the rotating table over the pallet conveyor; and (f) unloading the roll of roofing material from the rotating table onto the pallet. The pallet is positioned stationary relative to the loading position of the rotational table throughout the process.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.